43Q POPULAR SCIENCE MONTHLY 



an inability of the body to oxidize the sugar. In diabetes the excess of 

 sugar then is removed by the kidneys. In obesity the fat is not re- 

 moved, but accumulates in adipose tissue. The explanation of both 

 conditions would be an inability of the body cells to oxidize these sub- 

 stances. Herter states the points of similarity of the conditions thus : 



1. Diminished oxidation of both materials. 



2. The two conditions are frequently associated. 



3. In each case the defective utilization of nutritive materials is 

 more or less closely associated with substances produced by certain 

 glands. It has been clearly proved that disease of, or removal of, cer- 

 tain groups of cells imbedded in the pancreas, known as the ' islands of 

 Langerhans,' cause the appearance of sugar in the urine. And no 

 doubt remains that many of the cases of diabetes are primarily disease 

 of the pancreas. On the other hand, obesity may depend on the sus- 

 pension of function of other glands. The removal of the sexual glands 

 is commonly, though by no means invariably, followed by the laying on 

 of fat. This fact is taken advantage of by the poultryman in supplying 

 capon for the market. Members of the human species may be similarly 

 affected. 



But the gland showing the most intimate relation between its 

 function and obesity is the thyroid. This gland is situated in the 

 neck, on either side of the trachea. Its enlargement constitutes goitre. 

 Its absence or disease result in cretinism and myxcedema. When por- 

 tions of the dried gland of a sheep are mixed with the food of the 

 normal or obese individual marked bodily changes result. The results 

 of thyroid feeding in men and animals have been well summarized by 

 Eichardson. 4 In the first place, there is a marked increase of oxygen 

 consumption and carbonic acid excretion, that is, some constituent of 

 the gland promotes oxidation. This is accompanied by a loss of weight. 



The oxidation is not, however, selective of the fats alone, for most 

 observations have shown that there is an increase in the elimination of 

 nitrogen. This would mean that proteid is being consumed as well as 

 fat. If an animal was in nitrogenous equilibrium at the beginning of 

 the experiment, we should expect it to be considerably weakened by its 

 consumption of its own protoplasm. If, however, the nitrogenous food 

 is increased, while thyroid substance is being fed to the animal the con- 

 ditio^ of nitrogenous equilibrium can again be restored, and the subse- 

 quent loss of weight will be due chiefly to the oxidation of fat. The 

 above statement makes it clear that the question of the amount of fat 

 in any individual is a very complex one, depending on such a variety 

 of factors as condition of digestion, appetite, character and quantity of 

 food, amount of exercise and the proper working of a number of body 

 glands. 



* ' The Thyroid and Parathyroid Glands,' Hubart Richardson, 1905. 



